Field of the Invention
The disclosure relates in general to a display panel, and more particularly to a display panel with varying conductive pattern zone.
Description of the Related Art
Today, electronic products with displays panels, such as smart phones, tablet personal computers (i.e. tablet PC, flat PC, ex: iPad), laptops, monitors, and televisions, have become indispensable necessities for working-processing-learning or personal leisure entertaining in the daily life of the modern human beings. Penetration of water vapor/oxygen into the displays panels has considerable effect on the operation lifetime of the electronic device. It is known that the organic light emitting diode display (OLED) has the most severe requirement on the water vapor/oxygen blocking rate.
Since the organic materials and metal cathode of the OLED are highly sensitive to water vapor and oxygen, the device will be deteriorated soon after penetration of water vapor and oxygen. It has been proposed by the researches that the required water vapor transmission rate (WVTR) of a commercial OLED is typically not over 1×10−6 g/m2/day, and the oxygen transmission rate (OTR) is typically not over 10−5 to 10−3 cm3/m2/day for reaching 10000 hours of the operational lifetime. To maintain or even improve the electrical performances of the device and also the operation lifetime and reliability of the display panel, it is necessary to perform the packaging well, such as good adhesion between the opposite substrates of the display panel.
In the assembly of the display panel, the upper and lower substrates are adhered to each other by the sealant. For example, a sealant dispensing area of a TFT display panel extends across the metal regions (comprising the power line, data lines, signal lines, . . . ) on the TFT substrate. Practically, the sealant can be melted at a high temperature; for example, the sealant is typically irradiated and melted by the laser (WVTR of a well-hermetical OLED is typically not over 1×10−6 g/m2/day), and the laser beam travels along the metal traces and metal blocks. Some of the laser energy is absorbed and/or reflected by the metal portions which creates an uneven temperature distribution in the frit (metal having high reflectivity and good thermal conductivity) during the sealing process. Therefore, different properties between the metal regions and non-metal regions lead to considerable differences of thermal conductivities which may cause the problems of crack on the sealant and insufficient connection between the substrates. Those problems are also easy to occur at the regions near the boundaries between the metal regions and non-metal regions due to high differences of temperatures in the sealing process. The faulty packaging and assembling of the display panel will lead to the decreases of the yield and reliability of production of the display panel.